A conventional wind power generating apparatus is provided with a horizontal-axis wind turbine with vanes, such as of the propeller type or the Dutch type. In the wind power generating apparatus, a yaw control apparatus is used to cause the wind turbine to point directly into the wind according to the wind direction that may vary from moment to moment. The yaw control apparatus can only turn the wind turbine within a certain range. The yaw control apparatus cannot cause the wind turbine to point directly into the wind, which may blow from any direction in 360 degrees.
Further, to prevent electric cables and the like installed within the apparatus from being twisted as the wind turbine turns, the range of turning of the wind turbine is limited to within a certain range. In order to untwist the electric cables and the like, the wind turbine may have to turn in the opposite direction.
On the other hand, there is a wind turbine apparatus equipped with a vertical-axis wind turbine, such as the Darrieus type and the Savonius type. The wind turbine apparatus of these types has the advantage that the wind turbine can be rotated by receiving wind from any direction in 360 degrees without having to turn the wind turbine.
In the vertical-axis wind turbine, a blade that rotates in the same direction as the direction of movement of wind can receive the wind and rotate in the same direction as the direction of movement of the wind. However, a blade on the opposite side would rotate in a direction opposite to the direction of movement of the wind. Thus, the rotating force of the wind turbine is weakened.
In order to overcome this problem, a baffle plate is fitted in many cases. The baffle plate can gather wind such that the wind hits the blade on the side that rotates in the same direction as the direction of movement of wind but does not hit the blade on the side that would rotate against the direction of movement of wind.
However, the baffle plate itself may be fixed and unable to move. In this case, the baffle plate does not work at all, depending on the wind direction. As a result, the aforementioned problem cannot be overcome.
In an invention disclosed in Patent Document 1, for example, a vertical-axis wind turbine is fitted with a weathercock blade that moves around a wind-receiving rotor according to the wind direction. According to this invention, the baffle plate and the weathercock blade are operatively linked so that the baffle plate can be rotationally displaced to a correct position at all times according to the wind direction. Thus, even under a condition such that the wind direction is frequently changed, the baffle plate can be automatically rotated to track the change in wind direction. Accordingly, the rotating force of the rotor can be effectively increased. As the baffle plate is moved according to the wind direction, the aforementioned problem can be overcome.